Cardiocirculatory aiding device

ABSTRACT

Cardiocirculatory aiding device, as hematic pumping device able to aid the right or left ventricular or biventricular of the human body, characterised by being supplied by gas pneumatic energy, in which: i) the variation of pressure generator device systems is intended for being placed outside of the human body; ii) the pumping device of the blood (P), is conceived to be installed inside of the human body; iii) the two said devices (i,ii) are connected with at least one tubular duct of transmission of said gas, passing from the inside of the human body to the external of the same; iv) said pumping device of the blood (P) being driven by the variation of pneumatic pressure in said duct by means of two opposite expansible and retractable lungs that compress a central chamber body elastically yielding by pulses in order to cause, by means of two ducts respectively of blood entry and blood exit with unidirectional valves, the pumping of the blood.

This application claims priority of Italian Patent Application No.UD2005A000112 filed on Jul. 1, 2005.

FIELD OF THE INVENTION

This invention relates to a cardiocirculatory aiding device, namely, toa hematic pump to be associated to the heart, whose characteristics arein accordance with the precharacterizing part of the main claim.

The use is substantially directed to assist the heart, but also toreplace it in extremis with two of these elements (Right and Left).

BACKGROUND OF INVENTION

As known in the cardiosurgery practice, some mechanical aiding devicesof the heart are used, commonly defined Ventricular Assist Device(V.A.D.) or Total Artificial Heart (T.A.H.).

We refer substantially to devices able to mechanically pump the blood,producing pulse or continuous hematic flows.

Such devices are used to solve reversible acute cardiac insufficiencyclinical cases (e.g.: infarct, myocarditis, morphological pathologies,postcardiotomy, etc . . . ) or are used for supporting the circulatoryfunction awaiting a heart transplantation or even indefinitely in caseof situations or irreversible chronic problematic pathologies “Therapydestination”.

Different ventricular aid devices have been present for many years, forboth left and right aid or biventricular (T.A.H.); some of them arecommercially available, other have been developed only to experimentallevel.

PROBLEMS AND DRAWBACKS OF THE BACKGROUND ART

In the majority of the cases the existing devices have some difficultiesof housing inside the chest, due to dimension and weight problems, aswell as in the application modalities.

Other noticeable drawbacks are due to their internal geometries and totheir pumping modalities that can cause, in respect of the blood,hemolysis or formation of coagulations.

Another negative aspect is caused by the weight and the encumbrance ofthe operating unit, associated to the pumping device that limits orprecludes the portability of the whole complex.

An additional problem created by the current devices is that theyinclude complex internal mechanisms and, given the complexity, they arenot completely reliable.

In fact it is known that the more an apparatus is complex, the moreprobabilities of jamming danger there are.

Furthermore the well-known devices incorporate electric and/orelectromagnetic apparatus, with all the consequences and the dangersthereof.

Finally it is known that such apparatus need more separate groups thatmust be housed in different positions of the body with furthercomplications and important encumbrances and infection danger.

Furthermore in case of jamming or stopping of the device, there is poorimmediate possibility of intervention from outside, endangering theuser's life.

SCOPE OF THE INVENTION

The scope of the invention is to solve the above-mentioned problems anddrawbacks, by simplifying strongly the apparatus and furthermore:

-   -   to improve the functionality and performances;    -   to increase the performance;    -   to improve the reliability;    -   to adjust easily the apparatus;    -   to reduce its encumbrance and its weight;    -   to eliminate any electric part to be installed inside of the        human body;    -   to be able to intervene in case of emergency from the external        of the human body without the necessity of complex apparatus,        but being able to pump in emergency also with the simple use of        the hands;    -   use in pediatric cases.

SOLUTION OF THE PROGRAM AND DISCLOSURE OF THE INVENTION

The problem is solved with the characteristics of the main claim.

The subclaims represent advantageous preferred solutions that supplybest performance.

ADVANTAGES

In this way, there is the advantage to extremely simplify the apparatusgiving the maximum performance guarantee to the user.

Moreover, thanks to the installations of the motor and electric orelectronic components, set outside, everything will be easily accessiblefor maintenance and change and will be also easily adjustable.

A further interesting advantage derives from the fact that the propellermeans is a gas (e.g. oxygen or air).

Furthermore, if the pumping external mechanism would clog or stop, amanual pumping means is provided. In fact, a simple small pump connectedto the pipe of the gas can be pressed in emergency also by the sameuser, regularly cadencing the pumping with a sole hand.

The gas loss danger, as propeller means inside of the body is avoided bythe current techniques that ensure the gasproof.

In fact the flexible tube of the gas can be carried out in a whole withthe respective expanding elastic chamber for example with siliconelastomeric materials (silicon rubber) that ensure a perfect and safecompatibility with the human body, see for example the enormous numberof silicon prosthesis in the human body (e.g. woman breasts).

For rigid and semirigid structural parts, the dacron can beadvantageously used, as already notoriously used in the bypass and inthe aortic aneurysms, in valve structures and artificial heartily parts.Naturally also other materials can be used as carbon plastic materials(e.g. pyrocarbon) or also metallic materials e.g. titanium, or any otherexisting or future technologically suitable and compatible materialaccording to the claims.

BRIEF DESCRIPTION OF DRAWINGS

A preferred embodiment of the cardiocirculatory aiding device accordingto the invention, will be now described, as a non-limitative example,referring to the drawings in which:

FIG. 1 shows a side sectional view X-X of the device;

FIG. 2 shows a front sectional view Y-Y of the device;

FIG. 3 represents a cross sectional view Z-Z as regards to the previousones;

FIG. 4 represents the circuit schema of the device connected to theelectro-pneumatic operating unit (7) by means of a hose-pipe (8) and thetranscutaneous passage (9).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The model according to the invention is made up essentially of a casingconsisting of two sealed opposite rigid shells (G1,G2).

Inside the rigid shells is clamped a core (1) in the form of a semirigiddiscoidal central chamber substantially in DELRIN (hemato-compatiblepolyammidic resin) with opposite flat walls, which are slightly yieldingor flexible, to perform the function of pumping. Inside the centralchamber (1) occurs the circulation of blood with the help of tworespective in-out ports with unidirectional valves (entry 5, exit 6).

Inside of these two rigid shells, interposed to the opposed faces of thecentral chamber body (1), there are two opposed flexible and/or elasticchambers (2, 3) for example in silicon elastomer material, that work astwo lungs on the contrary that, inflating, are used for pressing in apulsating manner the central chamber (1) giving the action of pulsepumping for deflection of the respective opposite faces, by means ofentry and exit ducts of the blood (5,6) associated with the saidunidirectional valves, which are technically known (not shown).

Externally, the apparatus appears in the form of a cardioid, wherein inthe lower apical zone is a pipe carrier joint (4) for the connection tothe pneumatic energy source that must feed the two opposite chambers(2,3).

On the opposed side of said pneumatic joint, there are the two bloodpumping mouths of opportune diameter: one is used for the entry of theblood (5) and the other (6) for the exit. Both are equipped withrespective unidirectional valves not shown.

It is understood in this way that, pressing the central chamber (1), theblood exits from the duct (6) being prevented to reflux in the duct (5)from the respective one-way valve, whereas the central chamber volume(1) returns in position for elastic restarting of the membrane, it sucksby the duct (5) the suctions from the duct being not allowed (6) for therespective one-way valve. In this way a classical sucking-pumping pumpis obtained, the mechanical parts and gaskets not being subjected towearing.

The aforementioned mouths are manufactured to be easily connected tohemocompatible hoses, commonly used in the cardiochirurgical techniques(e.g. hemocompatible polyammidic resin as DACRON).

A tube connected to the mouth (5) is used to take the blood from anatrium of the heart (e.g.: by means of atrioventricular cannula) or fromother zones of the cardiovascular apparatus; a tube connected to themouth (6) is used to restore the blood under pressure to theblood-vessels of the systemic circle or of the pulmonary circle,according to the type of the selected ventricular aid.

The internal cavity (central chamber) of the core (1), where thecirculation of blood takes place, separates the peripheral zone(inflatable chambers as opposite lungs 2, 3), seat of the pneumaticenergy.

Said elastic and/or flexible opposite chambers, can be of differentnature and form, and impress to the blood the necessary pressing energy.

The peripheral zone is closed by means of shells G1 and G2.

The said opposite flexible chambers (2, 3), with pressure increasefollowing gas inlet, inflate and vice-versa, therefore in associationwith the respective unidirectional valves in the ducts of the blood, theblood pumping by means of the volume variation to the central internalchamber (1) is obtained.

This concerns in conclusion a closed pump of the type with oppositemembrane, but in which there is no membrane (in this specific case, thetwo opposite walls of the central container 1 act as closed andintegrated membranes in the container for safety such as walls of thesame container 1), whose pulse is induced by compressed gas (for exampleoxygen or air) pumped from outside through a thin cannula (8) passingthrough the user's body (9) and transmits the pulses of pressure fromrespective external motor-driven pump (7-10) applied externally of thehuman body and therefore easily controllable and adjustable.

In this way, no electric apparatus is applied inside the organism.

The hematic flow that we can obtain is pulsatile.

The pneumatic energy is therefore characterized by pressing anddepressing waves from an external pump, which is necessary for thereciprocating movement of the opposite flexible elastic chambers.

The external pump can be an electro-pneumatic operating unit (7),powered by a battery and/or accumulators (10).

Obviously, the external pump can be of any type, namely piston ormembrane operated by cam, etc.

FURTHER CHARACTERISTICS

This device has a core (1) substantially rigid or semirigid, but whoseopposite walls can flex for the pumping of the blood, whose internalgeometry is shaped hydrodynamically in such a way as to avoid stagnatezones of the blood that may involve the formation of thrombus (internalwashing of the ventricular cavity carried out by a rotary flow of theblood).

Therefore, the separating element between the blood and the gas thattransmits the pneumatic energy is not only the walls of the centralcontainer (1), but also the presence of two elastically flexibleopposite chambers (2,3), therefore contractible and expandable,performing the pumping function in opposite way to the nucleus havingthe central sealed chamber (1).

The presence of said flexible chambers separating the blood and the gas,whose contraction and constraint modalities impose to said oppositechambers a mechanical stress rationally distributed, results as anadvantage for their long-time duration.

The symmetry and the contemporaneity of the movement of the oppositechambers allow avoiding the inertial actions that could makesussultatory the working of the device.

The electro-pneumatic operating unit (7), availing to known artelectro-mechanic devices, results compact and light such as to betransported by the carrying-person of the device, in a small bag, orhooked to a belt.

Such operating unit (7-10) rehabilitates the previous realizationattempts of pneumatic unit, little used, not for their performances, butfor the weight and the encumbrance that up to now have made themprohibitive for portability characteristics.

In fact, the activation by means of pneumatic energy is extremely lightand allows to build equally lightweight and of strongly-reduced sizeaiding devices, unlike the models containing inside electric motors,electromagnetic actuator and other mechanisms.

The aforementioned operating unit can own regulating devices, bothmanual and automatic, which allow a wide variation of flow emitted bythe aiding device.

The beat-frequency imposed to the device can be indicatively between90-180 pulses/min. and can be varied, both manually and automatically,by means of regulating systems present in the electro-pneumaticoperating unit 7.

It is understood from the above that the media flow emitted by thedevice strictly depends on the asynchronous beat-frequency.

Concerning the synchronism deficiency between the natural heart-beatsand those of the aiding device, it has been shown, both experimentallyand clinically, that the method of the ventricular assistance, by meansof high-frequency asynchronous pulses, is not in conflict with theprinciples of a correct hematic perfusion and how this method does notnegatively influence on the behavior of the assisted natural ventricle.

It has been furthermore verified that, taking into consideration the useof low range devices, the wished media flow values are also reached withthe increase of the frequency.

Only following this strategy and depriving the inside of the motorapparatus aiding device, as in the case in object, it is possible torealize elements that for their small size and the low weight are reallyimplantable inside the chest.

Such affirmations are comforted by the fact that at present aidingdevices ventricular based on the principle of the centrifugal pumpsexist and have been experimented, which are therefore able to supplyonly a continuous flow and therefore absolutely out of any possiblesynchronization with the cardiac pulsation.

While with the method of the continuous artificial perfusion anypossibility of synchronism between the diastolic systolic phases of theassisted heart is missing, as regards to those of the aiding device, incase of the asynchronous pulses with high frequency, the physicalphenomenon of the beats between the frequency of the assisted heartoccurs, as regards to the frequency of the assistance ventricle.

Namely the ventricle of the assisted heart is also periodically incorrect relation of phase with the aiding device and, only in suchsituation, can exhibit a natural reduced pressure range.

Obviously the details can however vary and the components can be builtin polymeric material or with substances of other hemocompatible nature.

Said particulars can be joined between them by means of screws, welding,sticking or other methods.

Inside the suction and delivery unidirectional valves, with spontaneousopening, of the type of those used in the valve change surgicalinstallations, it is however possible to use valves of other naturespecially manufactured fitted to be housed at the entry of the openings(5 and 6) of the central body (1).

More advantageously said unidirectional valves can be housed outside themouths (5 and 6), namely be inserted inside the connected hoses to theaforementioned mouths.

In this way, there is obviously greater operative security andintervention is easier and more silent.

Also advantageously, the core (1), whose internal cavity, interested bythe hematic flow, can be realized by means of a geometry with reducingsection towards the bottom opposite to the ducts (5, 6), that allows theblood to flow without meeting stagnate zones and to be pushed withouttrauma.

These characteristics allow avoiding, as much as possible, both problemsof thrombogenesis and hemolysis.

Also advantageously, the pneumatic connection between the operating unitand the pumping gas engagement (4) occurs by means of the hose (8) thatis of small diameter and is built-up in flexible plastic material andendowed with opportune aseptic transcutaneous passage (9).

The electro-pneumatic operating unit (7), produces a pulse gas flushing,whose frequency can be varied both manually and automatically.

Said electro-pneumatic operating unit is supplied by an electricaccumulator (10) that can also be housed inside of the unit (7).

Advantageously, the said opposite elastic members that face on thecavity of the core (1), operate substantially as two inversely operatinglungs, such to impress to blood a symmetrical push.

From such characteristic, results the fact that the aiding device iswithout mechanical oscillations or of winces provoked by underbalancingor inertial forces that can be originated from the internal dynamics ofthe device.

Said elastic chambers are advantageously movable.

They can also be extractable and interchangeable.

The movable parts are submitted to a mechanical stress uniformlyapportioned, which assures a long life.

The pulse device is advantageously asynchronous with the natural heart,to be for delivery for fixed pulse and being able to work to a variablefrequency in order to obtain a wide variation of mean flow.

Advantageously, the external pumping device can be completed in thepreferred solution, from a very simple emergency manual small pumpsimilar to a flexible pear, with exclusion valve.

In this case, at the jamming of the external pump, it will be sufficientto open the valve of the rubber manual pump and to pump manually.

A circulatory effect on the blood will thus be in that case surelyassured in awaiting emergency.

1. Cardiocirculatory aiding device, as hematic pumping device able toaid the right or left ventricular or the biventricular or other, insidethe human body, characterized in that it is operated by pulse-gaspneumatic energy and in which: i) the variation of pulse pressure of thegas generator device is intended for being placed outside of the humanbody; ii) the blood pumping device (P), is conceived to be installedinside of the human body; iii) the two said devices (i-7-10,ii-P) areconnected with at least one tubular duct of transmission of said gas,passing from the inside of the human body to the external of the same;iv) said blood pumping device (P) being driven by the variation ofpneumatic pressure in said duct by means of pressure means effective ona central chamber, by pulses, in such a way to pump the blood, by meansof two openings respectively of blood entry and blood exit associatedwith unidirectional valves.
 2. Cardiocirculatory aiding device,according to claim 1, characterized in that the said pressure meansconsist in two opposite expansible elastically/flexibly chambers such totransmit the pulse of the gas to the said pumping central chamber of theblood.
 3. Cardiocirculatory aiding device according to claim 1,characterized in that said central chamber is a rigid-semirigid distinctcontaining body with only one entry duct and only one exit duct and inwhich said central body is slightly pressed on its opposite faces,flexing them alternatively by the inflation of said two oppositechambers.
 4. Cardiocirculatory aiding device, according to claim 1,characterized in that said valves are external to the said pump (P),namely applied in the respective entry and exit ducts of the bloodapplied to said respective mouths.
 5. Cardiocirculatory aiding device,according to claim 1, characterized in that said valves are incorporatedin the respective input and exit blood openings of the pump. 6.Cardiocirculatory aiding device, according to claim 1, characterized inthat said central chamber body has substantially a discoidal section,progressively decreasing at the opposite side of said entry and exitducts of the blood.
 7. Cardiocirculatory aiding device, according toclaim 1 characterized in that said tubular duct is of flexible plasticmaterial.
 8. Cardiocirculatory aiding device, according to claim 1,characterized in that said gas pulse pressure variation generator is anelectro-pneumatic operating unit that produces a pulse gas flushingwhose frequency can be varied both manually and automatically. 9.Cardiocirculatory aiding device, according to claim 1, characterized inthat the said opposite and elastically expansible chambers consist inelastic chambers that face on the cavity of the central chamber body,such to impress to the blood a symmetrical push.
 10. Cardiocirculatoryaiding device, according to claim 9, characterized in that said oppositeand elastically expansible chambers are movable, flexible andinterchangeable.
 11. Cardiocirculatory aiding device, according to claim1, characterized in that said variation of pressure generator device isasynchronous with the natural heart and is adjustable to variablefrequency in order to obtain a mean flow variation. 12.Cardiocirculatory aiding device, according to claim 1, characterized inthat it comprises a flexible small manual pump or the like, withexclusion valve and connection to the said duct for operating as analternative of pumping the gas, manually.